package com.eshop.eshop2021_v1.common;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

/**
 * @author: 若若叶
 * @date: 2021/10/6 14:39 FileName: CodeUtils Description:
 */
// 生产验证码的工具类
public class CodeUtils {
  private static char code[] = {
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'p', 'q', 'r', 's', 't', 'u',
    'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P',
    'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '2', '3', '4', '5', '6', '7', '8', '9'
  };
  private static final int WIDTH = 50;
  private static final int HEIGHT = 20;
  private static final int LENGTH = 4;

  public static void getvalidataCode(HttpServletRequest request, HttpServletResponse response) {
    // TODO Auto-generated method stub
    // 设置响应报头信息
    response.setHeader("Pragma", "No-cache");
    response.setHeader("Cache-Control", "no-cache");
    response.setDateHeader("Expires", 0);
    // 设置响应的MIME类型
    response.setContentType("image/jpeg");

    BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
    Font mFont = new Font("Arial", Font.TRUETYPE_FONT, 18);
    Graphics g = image.getGraphics();
    Random rd = new Random();

    // 设置背景颜色
    g.setColor(new Color(rd.nextInt(55) + 200, rd.nextInt(55) + 200, rd.nextInt(55) + 200));
    g.fillRect(0, 0, WIDTH, HEIGHT);

    // 设置字体
    g.setFont(mFont);

    // 画边框
    g.setColor(Color.black);
    g.drawRect(0, 0, WIDTH - 1, HEIGHT - 1);

    // 随机产生的验证码
    String result = "";
    for (int i = 0; i < LENGTH; ++i) {
      result += code[rd.nextInt(code.length)];
    }
    HttpSession session = request.getSession();
    session.setAttribute("loginCode", result.toUpperCase());

    // 画验证码
    for (int i = 0; i < result.length(); i++) {
      g.setColor(new Color(rd.nextInt(200), rd.nextInt(200), rd.nextInt(200)));
      g.drawString(result.charAt(i) + "", 12 * i + 1, 16);
    }

    // 随机产生2个干扰线
    for (int i = 0; i < 2; i++) {
      g.setColor(new Color(rd.nextInt(200), rd.nextInt(200), rd.nextInt(200)));
      int x1 = rd.nextInt(WIDTH);
      int x2 = rd.nextInt(WIDTH);
      int y1 = rd.nextInt(HEIGHT);
      int y2 = rd.nextInt(HEIGHT);
      g.drawLine(x1, y1, x2, y2);
    }

    // 释放图形资源
    g.dispose();
    try {
      OutputStream os = response.getOutputStream();

      // 输出图像到页面
      ImageIO.write(image, "JPEG", os);
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}
